TGEND Targeted Genetics Corp

Company-Sponsored Research Featured as One Of "Top Five Abstracts" at the Presidential Symposium at the American Society of Gene Therapy 2006 Annual Meeting Targeted Genetics Corporation (Nasdaq: TGEND) and the company's academic collaborators reported multiple advances in the field of adeno-associated virus (AAV)-based product development in eight abstracts at the American Society of Gene Therapy 2006 Annual Meeting, which took place May 31 - June 4. The reported data provide insight into how to optimize the delivery, activation and long-term expression of AAV-based therapeutic products. In the Presidential Symposium held June 3, Liang Zhang, a graduate student from the research laboratory of John F. Engelhardt, Ph.D., Director of the Center for Gene Therapy, and Professor, Department of Anatomy and Cell Biology, at the University of Iowa, presented data describing a novel mechanism that is important for efficient delivery of DNA by AAV type 2 (AAV2) following entry of the virus into target cells. Productive processing is essential for effective and long-term expression of genes delivered with AAV vectors. The Engelhardt laboratory presentation, "NADPH-Dependent Endosomal ROS is Critical for rAAV Capsid Processing During Infection" (Abstract #807), demonstrated that AAV2 stimulates production of reactive oxygen species (ROS) in the endosome and then utilizes these ROS to alter function of the virus' protein coat (capsid). Understanding of this process may aid in the development of improved AAV2 vectors or novel administration strategies. Targeted Genetics funded these studies through a Sponsored Research Agreement with Dr. Engelhardt's laboratory. "As we focus on commercializing novel therapies to treat significant unmet medical need, we recognize the importance of advancing the science that supports our technology platform," said Dr. Barrie J. Carter, Ph.D., chief scientific officer of Targeted Genetics. "By collaborating with leading academic scientists, we ensure that we have the ability to incorporate new findings into our product development efforts. We greatly value the relationships we have with leaders in the fields of basic and applied AAV biology and believe that our collaborative efforts ultimately will help to improve the lives of patients with serious diseases." Other key AAV findings reported by Targeted Genetics and its collaborators at the ASGT meeting include: -- Gene expression studies demonstrating the gene delivery efficiency of AAV2/1 vectors and showing a correlation between kinetics of expression and administered dose (Abstract #118). -- Demonstration that an intramuscular administration of a pseudotyped AAV1-based HIV vaccine results in the persistence of vaccine DNA in the injected muscle. These findings are consistent with similar studies of an AAV2-based HIV vaccine and provide additional evidence that AAV-based vaccines may result in longer-term immune stimulation than can be achieved with other vaccine approaches (Abstract #492). -- Evaluation of the pathways through which AAV2 vectors traffick and ultimately express genes. This study demonstrates the presence of two distinct trafficking pathways, one of which was determined to be more effective for vector transduction. Pathway selection appears to depend on the dose of virus to which the cell is exposed. These findings provide an opportunity to further optimize vector dose and target the more effective trafficking pathway (Abstract #106). -- Two studies evaluating gene delivery to the lung. One study demonstrates that AAV2/1 is more efficient at transducing airway epithelial cells than other AAV serotypes and highlights the differences in biology of AAV2/1 compared with AAV2 or AAV2/5 (Abstract #10). The other study reports significant species-specific differences in the biology of electrolyte transport in airway epithelia as well as the ability of AAV vectors to transduce airway epithelial cells. These findings suggest the need for additional models in which to evaluate gene delivery to the lung (Abstract #1). Additional abstracts presented at the conference by two of Targeted Genetics' collaborators provide updates on the preclinical programs for two of Targeted Genetics' product candidates. Data from our collaboration with Sirna Therapeutics, Inc. using AAV vectors and RNA inhibition to develop novel therapies for Huntington's disease were presented in Abstract #414. Data from our collaboration with Celladon, Inc. using AAV to deliver the SERCA2a gene as a treatment for congestive heart failure were presented in Abstract #557. About Targeted Genetics Targeted Genetics Corporation is a biotechnology company committed to the development and commercialization of innovative, targeted molecular therapies for the prevention and treatment of inflammatory arthritis, HIV/AIDS and other acquired and inherited diseases with significant unmet medical need. Targeted Genetics uses its considerable knowledge and capabilities in the development and manufacturing of gene delivery technologies to advance a diverse product development pipeline. Its product development efforts target inflammatory arthritis, HIV/AIDS, congestive heart failure, Huntington's disease, and hyperlipidemia. To learn more about Targeted Genetics, visit its website at www.targetedgenetics.com. Safe Harbor Statement under the Private Securities Litigation Reform Act of 1995: This release contains forward-looking statements regarding our intellectual property, research programs and clinical trials, our product development and our potential development platforms including AAV vectors and other statements about our plans, objectives, intentions and expectations and other statements about our plans, objectives, intentions and expectations. These statements, involve current expectations, forecasts of future events and other statements that are not historical facts. Inaccurate assumptions and known and unknown risks and uncertainties can affect the accuracy of forward-looking statements. Factors that could affect our actual results include, but are not limited to, results of animal research are not necessarily indicative of results in humans, the timing, nature and results of our research, potential development of alternative technologies or more effective products by competitors, our ability to obtain and maintain regulatory or institutional approvals, our ability to obtain, maintain and protect our intellectual property and our ability to raise capital when needed, as well as other risk factors described in Item 1A. Risk Factors in our report on Form 10-K for the year ended December 31, 2005 and updated in Item 1A. Risk Factors in our Form 10-Q for the quarter ended March 31, 2006. You should not rely unduly on these forward-looking statements, which apply only as of the date of this release. We undertake no duty to publicly announce or report revisions to these statements as new information becomes available that may change our expectations.